I would be concerned about any air system maintenance procedure that had air lines being disconnected and reconnected unless that procedure was done by a qualified mechanic. But, this is not a recommended procedure in anything that I've read.
There is some discussion of clearing the air system of water in the Freightliner Chassis manual, which is available online at https://secure.freightliner.com/newb...MM_manuals.asp
Other authoritative information on air brakes is in the air brake licensing manuals that are used in Canadian Provinces. Here is the Manitoba link, for example https://www.mpi.mb.ca/en/PDFs/
There are three air drain lines on my Freightliner Custom Chassis, and I think this is common across all the FCC product line. They are in the front wheel wells. If the suspension is aired up, you can usually see the lanyards. Otherwise, turn the front wheels for a better view. Freightliner says you just need to drain them for a brief period. Others say to drain the whole air tank. If possible, have someone pull the lanyard while you watch below for water escaping. Or, do it on a dry patch of pavement to see if any water comes out. If water comes out of any of them, do a longer drain procedure and more frequently.
If you are driving in a humid area, this could be something to worry about. I've never seen water come out in my 15,000 miles of driving.
With the engine running, when the air compressor governor cuts out (about 125 psi), you can hear a release some air from the air dryer. This is expelling any water that collects at the start of the system. On my machine, it seems that this is enough to keep everything dry. That system is called an ADIS (Air Dryer Integrated System).
Reading the Provincial drivers' manuals, you'll note other recommended safety procedures. In theory, you have to check the rear (foundation) brakes daily for excess slack. It is very hard to do this check, since you need to crawl under while the parking brake is released and look for slack in the push rod that actuates the brakes. I did the check once and found no slack at all. Presumably, my slack adjusters are working perfectly. Of course, at some point, they may gum up and be a problem, so an annual check is warranted.